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I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.

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So this is a shorter episode, much to Marna’s pleasure. (Personally I’m indifferent to show length, regularly listening to episodes of other podcasts that run to 1.5 to 2 hours.) It was very good to have a guest: Barry Lichtenstein. (I kept in the bit where I mispronounced his name, as I thought it a funny mistake [1] . You’ll find another piece of flubbing, again because it was... [More]

If a customer has Transaction goals [1] - for CICS or IMS - it’s possible to observe the CPU per transaction with RMF. But you have to have: Transaction rate CPU consumed on behalf of the transactions. This might seem like stating the obvious but it’s worth thinking about: The transaction rate and the CPU consumption have to be for the same work. Now, a Transaction service class... [More]

I’m writing this under a lovely cherry tree in my back garden, in cool shade on a warm summer’s day. Before you complain “that ain’t working” I’ll just point out this is on a Saturday afternoon. And the “air cooling” is what makes this post possible. Just this past week I began an experiment. As with all experiments I might continue with it, but I... [More]

Boy has this one been a “slow train coming” but I’m glad it’s out now. And it was fun making it. Especially the piece with Frank and Jeff. It’s a long listen; As always I’m comfortable with long podcast episodes. Enjoy! Episode 14 “In The Long Run” Show Notes Here are the show notes for Episode 14 “In the Long Run”. The show is called... [More]

Back in 2009 I wrote about Performance of the (then new) DFSORT JOIN function . This post is just a few notes on things that might make life easier when developing a JOIN application. Specifically the one I alluded to in Happy Days Are Here Again? when I talked about processing SMF 101 (DB2 Accounting Trace) records. And I wrote it having scratched my head for a few hours developing a JOIN... [More]

I’ve written a lot about DDF and SMF 101 (Accounting Trace) over the years. It turns out my code went backwards a few years ago, and with good reason. Let me explain. But before I do, recall “my code” refers to a DFSORT E15 exit that “flattens” SMF 101 records, extracting the DDF-related fields into fixed positions. Each input record leads to an output record (if it... [More]

This post follows on from Some Parallel Sysplex Questions, Part 1 - Coupling Facility . Again it’s a high level treatment. In contrast to Coupling Facility (CF), there is really only one type of resource: Signaling paths. But again application componentry is what brings it all to life. In this case it’s XCF groups and members. And the motivation for all this? Responsiveness and (CPU)... [More]

In Some WLM Questions I outlined my approach to looking at WLM implementations.
It was necessarily very high level, but the intention was twofold: To prime customers about the kinds of questions I might be discussing with them - if I ever saw their data. [1] To give anyone maintaining a WLM policy some structure. It remains my view that WLM needs care and feeding, on a not-infrequent basis. You... [More]

Long ago I added reporting on DB2 log writing to our code. At the time it was just to understand if a particular job or transaction was “log heavy”. That is, I was interested in the job’s perspective, and whether it was dependent on a high-bandwidth DB2 logging subsystem. A recent incident, however, gave me a different reason to look at this data: We were concerned with what was... [More]

I’m starting to write this on a train to London. (Not Paris.) [1] When I get there I’m going to present the “New Improved” “Even More Fun With DDF” pitch to the UK GSE zCMPA user group. I was done with the slides a few days ago - or so I thought. [2] Well, I got some “down time” earlier this week to work on my DDF code some more - which resulted in... [More]

It’s been a few weeks since we last recorded and it was good to get back in “the studio” again. As usual it’s quite a wide range of topics. We hope you enjoy them. Two technical notes: I have new headphones which reduced the amount of bleed through from my ears to the microphone. Not entirely perfect but better. I still have to go through a fair amount of clean up, which... [More]

Many people know I’m a bit of an Automation “nut” but like most such people I feel a smidgeon of guilt that I might: Be spending more time setting up automation than I save. Having too much fun with it. But let’s dismiss Item 2 straight away; Fun is an enabler and motivator in the best possible way. There’s little more satisfying than seeing well-targeted automation... [More]

This is a follow up to Machines (Back To Humans) and nothing to do with Mac-hinations . The ‘“Principle” Of Sufficient Disgust’ kicked in - as it so often does - about a year ago. The issues outlined in that original posted revolved around having only one way to identify a machine. My code accepted only one type of specification for a machine: 02-12345=EWELME A By the way... [More]

This episode came hot on the heels of Episode 11 . The next one will be somewhat further away, unfortunately. As usual it was fun to make, though not without its share of technical difficulties. Which is ironic, considering our “Topics” topic. We’re still playing with the “Zero Indexing” thing, as all good geeks should. Hence the title. Episode 12 “Baker’s... [More]

We recently went to z/OS 2.1 on our Production system in Greenford. And just last week I threw into Production some JCL that used two of the new z/OS 2.1 JCL changes, plus an oldie that might have escaped your attention. Now we are firmly on 2.1 we can exploit them, with the certainty of not having to revert them. I expect many of you are in a similar position. So here they are, with the context... [More]